Transcript Ch2 (22-54)
2 Concepts of Healing Healing By primary intention: Separation is small Bridge of cells binds ends of wound together Minor wounds, suture wounds By secondary intention: Separation is large Tissue must fill space More scar, longer healing time Tissue Healing Phases Inflammation Phase Occurs during first 3-5 days Complex cellular and chemical interactions take place Neutrophils abound Macrohages replace PMNs in 24-48 h to debride area Signs of Inflammation Redness Temperature increase Edema Pain Reduced function Causes of Inflammation The signs of inflammation occur because of the increased metabolic activity and fluid in the region and the tissue damage that has occurred. Loss of function is produced by the primary signs of inflammation. Proliferation Phase Duration: 2-4 weeks Angiogenesis and granulation tissue formation Increased fibroblasts by day 3-5 following injury; reduced PMNs Type III collagen formed By day 12, type I collagen replacing type III Signs of Proliferation Redness Swelling Pain Local temperature Remodeling Phase Lasts 6-18 months Myofibroblasts cause wound contraction to minimize scar Collagen transition—type I replaces type III Capillaries diminish in number Tensile strength increases Signs of Remodeling Reduced redness Reduced edema Reduced pain No local temperature Growth Factors Proteins Specific growth factors impact specific cells Named for target cells, source, behavior Perform important roles in healing process Roles of Growth Factors in Healing Control migration and proliferation of cells Affect fibrin-plug formation Control phagocytization Assist capillary endothelial production Stimulate type III collagen degradation, type I synthesis Ligament Healing Site fills with erythrocytes, leukocytes, lymphocytes. Monocytes and macrophages infiltrate. Fibroblasts appear, increase, produce extracellular matrix. Cellular and matrix structures replace the blood clot. Macrophages, fibroblasts diminish; type I collagen replaces type III. Near-normal tensile strength is restored at week 40-50. Tendon Healing Wound gap filled by phagocytes Collagen synthesis Fibroblast proliferation; revascularization; synovial sheath rebuilt Fibroblasts revert to tenocytes; type III collagen replaced with type I Strength is 85-95% normal at week 40-50 Muscle Healing Fragmentation of muscle fibers; macrophages appear Appearance of fibroblasts; reduced muscle tension; phagocytes Day 7: scar tissue; near-normal muscle tension can be produced Day 7-11: near-normal tensile strength Regenerating myotubes; crossstriated muscle fibers Contraction ability: 90% normal at 6 weeks to 6 months Articular Cartilage Healing Fibrin clot is formed Fibroblasts combine with collagen fibers to replace clot 1 month—Fibroblasts differentiate; chondrocytes appear 2 months—defect resembles cartilage, but collagen is type I 6 months—type I and II calcified cartilage with normal appearance Bone Healing PMNs, plasma, lymphocytes Fibroblasts invade Hematoma forms; fractured edges become necrotic Osteoclasts proliferate; hard callus develops External blood supply dominates; then medullary circulation reestablished 3-4 months: Fracture is healed Week 12: near-normal strength restored tensile strength: maximal amount of stress or force that a structure is able to withstand before tissue failure occurs—in this case, the amount of outside force that can be applied to a muscle, tendon, ligament, or bone before it tears or breaks Tensile Strength During Healing Phases Inflammation Rapid decline to 50% Source of tensile strength: fibrin clot Proliferation Increase in tensile strength Source of tensile strength: collagen, granulation tissue, ground substance (continued) Tensile Strength During Healing Phases Remodeling Bone 83% of normal in 12 weeks Ligament and tendon near normal in 17-50 weeks Full tensile strength never regained Healing and Tensile Strength For a therapeutic exercise program to be successful, one must have respect for the healing process and a knowledge of tensile strength factors. Factors That Affect Healing Modalities Medications/Drugs Other modifying factors (age, disease, etc.) Treatment Modalities Ice Electrical stimulation Superficial heat Deep heat Influence of Modalities on Healing Relieve pain, spasm, edema Enhance protein synthesis Retard atrophy, facilitate muscle activity Improve circulation Enhance collagen and neovascular production Promote myofibroblast production Factors in Medication Effectiveness half-life: the amount of time it takes for the level of a drug in the bloodstream to decrease by half steady state of a drug: the state in which the average level of a drug remains constant in the blood—the amount of drug leaving the body is equal to the amount being absorbed Effects of NSAIDs on Healing Inhibit prostaglandin production Increase blood clotting time Decrease the effectiveness of other drugs Absorption rate decreased when NSAIDs used with antacids Drugs That Can Delay Healing Antibiotics Antineoplastic drugs Heparin Nicotine Corticosteroids Other Modifying Factors That Can Affect Healing Surgical technique Age Disease Wound size Infection Nutrition Muscle spasm Edema Role of Therapeutic Exercise in Inflammation Phase Control edema and pain Limit tissue stress because of weakness of fibrin plug Avoid strengthening activities Role of Therapeutic Exercise in Proliferation Phase Tissue is weak but improving in strength with collagen production. Patient can start range-of-motion and limited strengthening activities. Exception is in tendon repairs. Role of Therapeutic Exercise in Remodeling Phase Progressive increase in tensile strength allows progressive increase in stress. Stress application must coincide with increase in tensile strength. Considerations for Appropriate Course Usual healing sequence and timing Individual’s unique response to the injury and treatment Signs of an Overly Aggressive Program Increased pain, especially postexercise Increased edema, especially if lasts more than 1 day postexercise Diminished function from the previous day’s treatment